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Essential Questions What do we know? What do we need to know? What is your estimate of the perimeter?

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Guided Practice SKETCHPAD EXERCISE Draw 3 points that are not collinear. Use the pointer tool to select the points. From the Construct menu, select draw an arc through 3 points. Use the line tool to draw lines to complete the figure. Use the pointer to adjust the shape of the figure. Highlight the lines and use the Measure menu to measure the length of each line. Impact Mathematics C1 page 485_2 nd ed.,2004 How to construct the figure on C1 page 43_3 rd ed.,2009 (C1 page 485_2 nd ed.,2004) :

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Circumference Download To A Circle.gsp Notice that as we add more sides to our inscribed shape, the closer it approaches a circle, and the closer the perimeter of the inscribed shape approaches the circumference of the circle. Getting Started

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Work Time Work in small groups to use Geometers Sketchpad to calculate the perimeter of various polygons. What happens when we add more sides to the inscribed shape? Discuss and display your work from the session.